This invention relates to methods of and means for cutting hose for high pressure hydraulic systems into lengths appropriate for use and more particularly to methods of and means for using a laser beam to cut high pressure hydraulic hose to length.
Hose for conducting the fluids of high pressure hydraulic systems must be designed to be flexible and wear resistant in addition to being fluid impervious and capable of withstanding the very high pressure of the fluids they conduct. Thus, a cross-section of such hose presents a complex arrangement of materials including rubber, reinforcing metal members and fabrics of natural or synthetic materials.
Such hose is most efficiently fabricated by substantially continuous processes resulting in very long lengths of hose which must be cut into sections of appropriate shorter length for subsequent use. In the prior art, various mechanical cutting techniques have been used to cut the hose to proper length. For example, a metal bandsaw has been widely used for this purpose. However, the dissimilarity of the materials of which the hose is made and the necessary strength of the metal reinforcing has made it necessary to use high quality bandsaw blades and to replace them often thus making the process of cutting the hose according to the prior art both expensive, in terms of operational cost, and time consuming. In addition, the quality of the cut provided by prior art processes tended to be reduced by the tendency of certain of the materials to tear or be weakened by the cutting process.
According to this invention, a high power laser beam is used to cut the hose resulting in a saving in both operational cost and time. In addition, it has been found that the cutting process of this invention results in a cut of improved quality in that there is no tearing or weakening at the cut of the various materials of which the hose is made or of their structural interrelationship with each other.
Cutting of composite materials such as rubberized wire has been proposed heretofore. For example, U.S. Pat. No. 3,870,852 to Kogert discloses a process and apparatus for cutting a rubberized stranded wire web with a CO.sub.2 laser beam. However, according to the teaching of Kogert, it was necessary to clamp the web of rubberized wire between heat sink means adjacent the cut in order to prevent destruction of the rubber coating adjacent the cut. Such teaching is obviously inapplicable to the cutting of high pressure hydraulic hose due not only to the mechanical difficulty of providing the necessary heat sink at the interior surface of the hose but also to the wall thickness of such hose which renders it impossible to provide the requisite cooling throughout the depth of the cut.
It is the primary object of this invention to provide a method of and means for cutting hose for high pressure hydraulic systems through the use of a laser beam.